Elevator system

ABSTRACT

A new and improved elevator system, and method of directing a plurality of elevator cars to serve floor calls in an elevator system. Service is provided for a floor call by either allocating the floor call to a suitably conditioned elevator car which is busy serving one or more calls for elevator service, or by specifically assigning a non-busy car to serve the call. The floor calls which are in the elevator system at any instant are periodically reprocessed. The manner in which a call is reprocessed depends upon whether it is allocated to a busy car, or processed by assigning a non-busy car to it. The assignment of a car to the highest down call in the building at the time the call is processed is not changed to a higher down call subsequently registered if there is another non-busy car which can be assigned to the subsequent down call. When all cars have no assignment and no allocated calls, the system is reinitiated to cause any floor calls which may have been registered and for some reason not answered to appear as a new call in the system.

United States Patent [191 Sackin Dec. 3, 1974 l l ELEVATOR SYSTEM {57] ABSTRACT '75 Inventor; Milton Sackin Pittsburgh, p A new and improved elevator system, and method of directing a plurality of elevator cars to serve floor calls [73] Asslgnee: westmghouse Elecmc corporaton in an elevator system. Service is provided for a floor Pittsburgh call by either allocating the floor call to a suitably con- [22] Fil d; M 12, 1973 ditioned elevator car which is busy serving one or more calls for elevator service, or b s ecificall as- [21] Appl' 340615 signing a non-busy car to serve the call. 'I he floorialls which are in the elevator system at any instant are pe- 52 US. c|.... 187/29 R riodically reprocessed- The manner in which a call is [51] Int. Cl. B66b 1/22 reprocessed depends p Whether it is allocated o a [58] Field of Search 187/29 y car, Or Processed y assigning a y car to it. The assignment of a car to the highest down call in [56] Ref renc Cit d the building at the time the call is processed is not UNITED STATES PATENTS changed to a higher down call subsequently registered 3 443 668 5/1969 Han et 187/29 if there is another non-busy car which can be assigned 3:605:95l 9 1971 Kirschl.... .IIII:2:13:31: 187/29 to the Subsequent down when all cars have assignment and no allocated calls, the system is reinitiated to cause any floor calls which may have been registered and for some reason not answered to appear as a new call in the system.

21 Claims, 30 Drawing Figures THER 75 IMING 82 FUNCTIONS TIMING 7o INTERFAC common I i SYSTEM PRoczssoR flit/50L OTHER.CARS

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OLD DOOR N OPEN Y 392 398 N 399 1 y W 393 404 Y SET ZCCI SET NXTIM 397 N SET AVAD 40B W T?5O N J;

Y 409 I li 1402 DOOR NORMAL PATENTEL A 3.851.734

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Y N I 7 STTPARK MAIN FL 8 BELOW DOOR LANT NORMAL MF PARK L TASS-- DOWN sAss+ DOWN ASGN MODE=0O PARKAS MODE NORMAL DOOR 8 LA NT NORMAL,

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339 337 336 SET CAR N Y SET CAR 'DNPK DNPK OUTPUT UPDATE N UPDATE fig EXTRA ORD INPUT DATA PATENTEL BEE 31974 sum mar 18.

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RESET LOBMZD DEMIND HI T 65l DEMIND MZ DEMIND BSMT DEMIND 2 L0 DEMIND HI PROGRAM PROGRAM PROGRAM PROGRAM L i J FIND CLOSEST CAR OUTPUT ASSGMNT SET DEMAS MF RESET LOBMZD CROSS-REFERENCE TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION 1. Field of the Invention: The invention relates in general to elevator systems, and more specifically to elevator systems in which a plurality of elevator cars are controlled by a central dispatching control apparatus.

2. Description of the Prior Art:

Central dispatchers in the prior art used for dispatching a plurality of elevator cars to serve floor calls registered in the associated building or structure, usually employ many logic elements. Thus, central dispatchers of this type receive signals from the corridor call registers and from the elevator cars in parallel, they are processed in parallel, and in response thereto signals are output to the system in parallel.

If a digital computer were to be used for dispatching elevator cars to the task of serving floor calls in a building, the conventional prior art parallel approach to signal collecting, processing and generation is necessarily replaced by a serial approach due to the restricted number of logic elements in the processing function of the usual digital computer. In serial or sequential processing, each input signal is observed in turn, and each output signal is generated in turn. The signals are processed at very high rates, and they are at the relatively low logic voltage level.

Thus, it would be desirable to insure that service is not delayed to a call for elevator service because it somehow became lost in the system during processing, or because it is considered erroneously by the system processor as being answered when in fact the call has not been placed in the assignment register of any of the cars.

In the prior art, the highest down call registered receives special priority, and when a car is assigned to answer the highest down call registered its assignment will be changed if, while on its way to answer this call, a second and still higher down call is registered. The first call, now unassigned, will be assigned to another available car, or the next car that becomes available, i.e., one not currently busy serving a call for elevator service. This arrangement often results in two cars traveling substantially the full length of the building, as the first car may have been the closest available car to the first highest down call registered, but it may not be the closest car to the subsequently registered highest down call. An available car near the second call will not be assigned to the second call, as the first call will automatically be assigned to the subsequently registered highest down call. Thus, the second car may be assigned to the first call.

SUMMARY OF THE INVENTION Briefly, the present invention is a new and improved elevator system, and method of dispatching cars in an elevator system, to serve calls for service therein. A programmable digital computer system processor is used, with sequential processing of data, and sequential generation of command and status signals. The floor calls are placed in a call table, with new floor calls being allocated to the closest suitably conditioned elevator car which is already busy serving calls for elevator service, and if the call cannot be so allocated, a demand signal is generated relative to the call. The closest non-busy or available car is assigned specifically to a demand call.

The floor calls are marked in the call table when they are allocated to a car, or processed by assigning'a car to them, and they are also marked as to whether a demand signal was created for them.

To prevent floor calls from becoming lost" for some reason, and to provide the most efficient elevator service by updating certain types of assignments, the whole call table is processed at rapid intervals, which includes calls previously processed. The invention distinguishes between the two categories of processed calls, providing a different strategy for calls which were originally processed by allocation to a running call and those originally processed by assigning a non-busy or available car to the call.

If the call was originally processed by assigning a car to the call, the call is marked as an assigned-demand call in the call table. The strategy is to confirm that a car has been given the assignment of stopping at the floor of this call, and if this is verified, the processing of this call is complete, and the assignment is not changed. If a car is not found with this assignment, the assigned status of the call is deleted and the call reprocessed by either allocating the call to the closest suitably conditioned busy or running car, or by creating a demand signal for it and assigning the closest available car to the demand call.

If the call is in the category of having been allocated to a car, it is marked assigned but not as a demand call. Upon reprocessing this category of call, the assigned status is always deleted and the call reprocessed by allocating the call to the closest suitably conditioned car, or by creating a demand signal relative to the call and assigning the closest available non-busy car.

If all of the cars become non-busy, i.e., they have no assignment, no floor call allocation, and no car calls, the invention follows an initialization procedure which is normally only used upon start-up of the system, which procedure clears the call table and car assignment tables. If there would happen to be a lost call for elevator service, it would then appear as a new call in the system and be processed in the same manner as a new call.

The invention retains the priority of the highest down call, and does so with a different strategy which prevents two cars from effectively changing places in the building, and thus it eliminates needless travel and shortens waiting time. When a down call is registered which is the highest down call and it cannot be allocated to a busy car, a demand signal is created which results in the closest available non-busy car being assigned to the call. If a higher down call is registered while the first car is on its way to its previously highest 

1. A method of allocating floor calls from a plurality of floors of a structure to a plurality of elevator cars mounted in the structure to serve the floors, comprising the steps of: providing call table means to which new floor calls are added and answered floor cals are deleted, periodically ordering the floor calls in the call table means such that the floor calls appear in the call table means in the order in which their associated floors are located in the structure, adding new floor calls received between ordering steps to an end of the ordered floor calls, providing an assignment register for each of the elevator cars, periodically processing only new floor calls located at the end of the ordered floor calls in the call table means by either allocating each new call to the assignment register of an elevator car which is in the process of serving a call for elevator service, or by creating a demand signal, periodically assigning elevator cars which are not in the process of serving a call for elevator service to floor calls for which a demand signal was created, processing all of the floor calls in the call table means following each ordering step, said processing step including the steps of: determining for each call if it is in the assigneddemand category of (a) having had a demand signal created for it, and (b) in response to the demand signal an elevator car was assigned to the call, verifying for an assigned-demand category call that an elevator car has been assigned to the floor associated with the call, proceeding to the next call when the verification step affirms that a car has been assigned to the floor of the assigneddemand category call, considering the assigned-demand category call unassigned when the verification step fails to affirm that a car has been assigned to the floor associated with The call, processing an assigned-demand category call considered unassigned by either allocating the call to the assignment register of an elevator car which is in the process of serving an allocated call for elevator service, or by creating a demand signal, considering floor calls not in the assigned-demand category as unassigned, and processing each of these floor calls considered unassigned by either allocating the call to the assignment register of an elevator car which is in the process of serving a call for elevator service, or by creating a demand signal.
 2. The method of claim 1 including the step of removing all floor calls from the call table means when all in-service elevator cars are in the category of not in the process of serving a call for elevator service.
 3. The method of claim 1 wherein the step of processing all of the floor calls in the call table means starts with the end of the ordered floor calls representing the highest call in the structure.
 4. The method of claim 1 wherein the step of processing all of the floor calls in the call table includes the steps of determining whether the floor call is an up floor call or a down floor call, and when it is a down floor call the step of processing the call to either add it to the assignment register of an elevator car or to create a demand signal includes the step of excluding elevator cars from consideration for call allocation when they have already been assigned to answer a floor call for which a demand signal was created.
 5. The method of claim 4 including the step of determining the highest down floor call, and when a suitable non-assigned car cannot be found during the processing step of the highest down floor call, adding the step of determining if there are any in-service cars not in the process of serving a call for elevator service, adding the step of determining the suitability of cars assigned to answer a call for which a demand signal was created if there are no cars in this category, and allocating the highest down call to one of these assigned cars if a suitable car is found.
 6. The method of claim 5 wherein the step of determining the highest down call is performed by starting the processing of all of the floor calls in the call table means at the end thereof which represents the top of the structure, wherein the first down floor call will be the highest down floor call.
 7. A method of allocating floor calls from a plurality of floors of a structure to a plurality of elevator cars mounted in the structure to serve the floors, comprising the steps of: processing a down floor call by considering the elevator cars relative to the call with a first set of requirements, allocating a down floor call to an elevator car if the processing step locates a car meeting the first set of requirements and otherwise considering the call unassigned, determining if an unassigned down floor call is the highest down floor call registered, creating a demand signal for the unassigned down floor call if it is not the highest down floor call registered, determining if there are any in-service elevator cars in the available category of not being in the process of serving an call for elevator service, creating a demand signal for the unassigned highest down floor call if there is a car in the available category, and assigning a car in the available category to the call, reprocessing the unassigned highest down floor call with a second set of requirements if there are no cars in the available category, and allocating the unassigned highest down floor call to an elevator car if the reprocessing step locates a car meeting the second set of requirements, and otherwise creating a demand signal for the call.
 8. The method of claim 7 wherein the step of determining if an unassigned down floor call is the highest down floor call registered includes the steps of providing call table means to which new floor calls are added and answered floor calls are deleted, periodically ordering the floor calls in the call table means such that the floor calls appear in the call table means in the order in which their associated floors are located in the structure, and processing the ordered floor calls from the end of the call table means representing the top of the structure, such that the first down floor call encountered is the highest down floor call registered.
 9. The method of claim 7 wherein the first set of requirements used by the processing step includes the requirement that a car not be already assigned to a floor call for which a demand signal was created, and the second set of requirements used by the reprocessing step eliminates this requirement.
 10. The method of claim 7 wherein the step of allocating a down floor call to a car located by the processing and reprocessing steps allocates the call to the car which is closest to the call floor if more than one car is found which meets the first and second sets of requirements, respectively.
 11. A method of allocating floor calls from a plurality of floors of a structure to a plurality of elevator cars mounted in the structure to serve the floors, comprising the steps of: providing call table means to which new floor calls are added and answered floor calls are deleted, providing an assignment register for each of the elevator cars, allocating calls in the call table means to said elevator cars, determining when all in-service elevator cars are in the available category of not bein in the process of serving a call for elevator service, and deleting any floor call in the call table means when all in-service cars are in the available category.
 12. A method of allocating floor calls from a plurality of floors of a structure to a plurality of elevator cars mounted in the structure to serve the floors, comprising the steps of: providing an assignment register for each of the elevator cars, processing new floor calls by allocating each new floor call to the assignment register of an elevator car which is in the process of serving a call for elevator service, or by creating a demand signal relative to the call, assigning an elevator car not in the process of serving a call for elevator service to a call for which a demand signal was created, periodically reprocessing at least certain of the floor calls, with said reprocessing step including the steps of: determining for each call reprocessed if it is in the assigned-demand category of having had a demand signal created for it and in response to the demand signal an elevator car was assigned to the call, verifying for each assigned-demand category call that an elevator car has actually been assigned to the floor associated with the call, considering the assigned-demand category call unassigned when the verification steps fails to locate an elevator car assigned to the floor of the call, processing the assigned-demand category call considered unassigned by either allocating the call to the assignment register of an elevator car which is in the process of serving a call for elevator service or by creating a demand signal relative to the call, considering as unassigned all reprocessed calls which are not in the assigned demand category, and processing each of these unassigned floor calls by either allocating the call to the assignment register of an elevator car which is the in the process of serving a call for elevator service, or by creating a demand signal relative to the call.
 13. The method of claim 12 wherein the step of reprocessing a floor call which is not in the assigned-demand category includes the step of locating the closest elevator car to the floor call having an advanced car position and service direction consistent with the floor call location and request for service direction, and which is already in the process of serving a call for elevator service.
 14. An elevator system for a structure having a plurality of vertically spaced fLoors, comprising: a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, down floor call registering means operable for registering a call for elevator service in the down direction from each of a plurality of said floors, up floor call registering means operable for registering a call for elevator service in the up direction for each of a plurality of said floors, car call registering means for each of the elevator cars operable for registering a call for each of a plurality of said floors which may be desired by load in the associated elevator car, assignment register means associated with each of said elevator cars operable to receive an assignment to serve predetermined floor calls, control means associated with each elevator car said control means being in a first condition when its associated elevator car is in the process of serving a call for elevator service and in a second condition when the car is not in the process of serving a call for elevator service, first processing means for either allocating new calls from said up and down floor call registering means to an elevator car whose control means is in its first condition or by creating a demand signal relative to the call, second processing means for assigning an elevator car whose control means is in its second condition to a floor call for which a demand signal was created, and third processing means for periodically reprocessing at least certain of the floor calls, including first means for verifying that a floor call to which a car was assigned by said second processing means actually has an elevator car assigned thereto.
 15. The elevator system of claim 14 wherein the third processing means includes second means for determining the most suitable car for serving a call which was allocated to a car by the first processing means.
 16. The elevator system of claim 15 wherein the second means includes means responsive to the advanced car position of the elevator car relative to the floor of the call being considered, the service direction of the elevator car and the service direction request of the floor call, determining the closest car to the call floor whose position and service direction are consistent with the call location and service direction request.
 17. An elevator system for a structure having a plurality of vertically spaced floors, comprising: a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, down floor call registering means operable for registering a call for elevator service in the down direction from each of a plurality of said floors, up floor call registering means operable for registering a call for elevator service in the up direction from each of a plurality of said floors, car call registering means for each of the elevator cars operable for registering a call for each of a plurality of said floors which may be desired by load in the associated elevator car, control means associated with each elevator car said control means being in a first condition when its associated car is in the process of serving a call for elevator service, and in a second condition when the car is not in the process of serving a call for elevator service, assignment register means associated with each of said elevator cars operable to receive an assignment to serve predetermined floor calls, collecting means for collecting floor calls from said up and down floor calls registering means, ordering means for periodically ordering the floor calls collected by said collecting means such that their locations relative to one another correspond to the relative locations of their associated floors in the structure, said collecting means adding floor calls collected subsequent to the ordering of the floor calls by said ordering means to an end of the ordered floor calls, first procEssing means for periodically processing certain floor calls collected by said collecting means by either allocating a selected floor call to the assignment register of at least one elevator car having its control means in its first condition, or registering a demand signal relative to the call, second processing means for assigning an elevator car having its control means in its second condition to a floor call for which a demand signal was created, said first processing means being responsive to said ordering means, processing all of the car calls each time and ordering means orders the floor calls, and otherwise only processing floor calls added to an end of the ordered floor calls, and third processing means for periodically reprocessing at least certain of the floor calls, including first means for verifying that floor calls assigned by said second processing means actually have an elevator car assigned thereto.
 18. The elevator system of claim 17 wherein the third processing means includes second means for determining the most suitable car for serving a call which was allocated to a car by the first processing means.
 19. The elevator system of claim 18 wherein the second means includes means responsive to the advanced car position of the elevator car relative to the floor of the car being considered, the service direction of the elevator car, and the service direction request of the floor call, determining the closest car to the floor call whose position and service direction are consistent with the call location and service direction request.
 20. An elevator system for a structure having a plurality of vertically spaced floors, comprising: a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, down floor call registering means operable for registering a call for elevator service in the down direction from each of a plurality of said floors, up floor call registering means operable for registering a call for elevator service in the up direction from each of a plurality of said floors, car call registering means for each of the elevator cars operable for registering a call for each of a plurality of said floors which may be desired by load in the associated elevator car, first control means associated with each elevator car, said first control means being in its first condition when its associated elevator car is in the process of serving a call for elevator service and in a second condition when the car is not, second control means associated with each elevator car, said second control means being in a first condition when its associated elevator car has been assigned to serve a specific floor call and in a second condition when it is not, first processing means for either allocating new calls from said down floor call registering means to an elevator car whose first and second control means are in their first and second conditions, respectively, and otherwise considering the call unassigned, call distinguishing means for determining if a floor call considered unassigned by said first processing means is the highest down floor call registered, demand signal means responsive to said call distinguishing means for creating a demand signal if the call is not the highest down floor call registered, availability means which is in a first condition when any one of the elevator cars is in service but not in the process of serving a call for elevator service, and in a second condition when all cars are in the process of serving a call for elevator service, said demand signal means being responsive to said call distinguishing means and to said availability means, creating a demand signal for the call when it is the highest down call registered and said availability means is in its first condition, second processing means responsive to said call distinguishing means and to said availability means when it is in its second cOndition for assigning an elevator car whose first and second control means are in their first conditions to the highest down call registered, or otherwise creating a demand signal for the call.
 21. An elevator system for a structure having a plurality of vertically spaced floors, comprising: a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, down floor call registering means operable for registering a call for elevator service in the down direction from each of a plurality of said floors, up floor call registering means operable for registering a call for elevator service in the up direction from each of a plurality of said floors, car call registering means for each of these elevator cars operable for registering a call for each of a plurality of said floors which may be desired by load in the associated elevator car, dispatching means for allocating registered floor calls to selected elevator cars, and assignment register means associated with each of said elevator cars operable to receive an assignment from said dispatching means, said dispatching means including: call table means for collecting new floor calls from said up and down floor call registering means, reset means for deleting floor calls from said call table means when an elevator car having a service direction consistent with the floor call service request stop at the floor of the call, control means associated with each of said elevator cars, said control means being in a first condition when the associated elevator is in the process of serving a call for elevator service, and in a second condition when it is not, and reinitializing means responsive to the control means of all of the elevator cars, said reinitializing means deleting all calls from said call table means when the control means of every elevator car is in its second condition. 